I've noticed of late a tend back towards skis being sold flat, much like the good old days! I'd not given much thought to bindings since when I last purchased skis (Head IM 72) the trend was towards integrated systems.
To cut a long story short I recently demo'd the Kastle MX78 (review to follow at a later date!) and found it to be the most versatile fun ski I have ever been on (I demo'd many skis in the last two years but I digress!). The ski was mounted with the Kastle K10 CTI binding, a two piece adjustable binding made by Marker for Kastle. I finally decided to purchase the MX78 and went with the K12 CTI binding (similar to the K10 but with a twin cam heel and higher DIN range) simply because I loved the way the MX78 skied with the K10. Again, love how the ski feels and am not looking to change a thing.
However, being curious, one rainy day I decided to see how having a boot inserted into a binding affected the ski flex on three different skis. My MX78 with K12 CTI, my Head IM72 with Railflex integrated binding, and an Atomic D2 VF 75 with the double deck technology. My testing was wholly unscientific and simply consisted of resting the skis tails on a firm surface while supporting the tips and loading the ski in the middle of the binding with and w/o a boot in the binding. I just eyeballed the result (I will look at taking some photographs and doing some measurements under different loads if I get sufficiently bored in the weeks ahead (not likely as we have big dumps in the forecast!)) and was surprised that I seemed to be able to see differences with the naked eye.
To cut a long story short, the MX78 with the CTI showed some degree of flattening around the boot sole with more flex occurring on either side of the boot. The same test in the Head with Tyrolia binding showed minimal effect but the flex did not seem quite as even as with no boot in the bindings. However, the effect was subtle and it really needs to be measured to be sure I am being fair.
The Atomic on the other hand - I could see no effect whatsoever. The black upper control deck visibly moved forward and the arc of the ski seemed very smooth.
OK, so this is very unscientific (three different skis after all) but I was surprised that any difference was apparent at all. Again, I way prefer the MX78 to anything else I have ever skied but am now curious as to how the ski might feel if it were mounted with a floating binding (I gather the Kastle KTi plate is center secured and floats at each end). I'd be interested to find pointers to any more scientific testing of the effect of various bindings on ski flex - i.e. anything measurement based. And also interested to hear peoples opinions on the effect of floating type systems on a skis ability to carve a clean arc (short, medium and long radius turns) and on turn flexibility vs 2 piece "fixed" systems.
Any and all comments welcome!